What we do know is that a horcrux is an object that a dark wizard or witch has hidden a fragment of their soul in. The process is fairly shrouded in mystery, however it is well-known that it involves a spell and a terrible act - including the most supreme act of evil - murder.

Today, Reddit user sirlionel13 offered up the explanation that the final, and most horrible act in the creation of a horcrux, is cannibalism.